Author Topic: SpaceX: General Falcon and Dragon discussion  (Read 1386049 times)

Offline mmeijeri

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SpaceX: General Falcon and Dragon discussion
« on: 10/25/2009 02:02 pm »
A new thread for general discussion of all things SpaceX, Falcon and Dragon, as this keeps dominating the updates thread.
Pro-tip: you don't have to be a jerk if someone doesn't agree with your theories

Offline mr. mark

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #1 on: 10/26/2009 11:32 pm »
Prediction: The first launch of Spacex's Falcon 9 launcher will be a complete success with first stage burn, stage separation and full 2nd stage burn. Elon Musk will announce that the Falcon 9 launcher is operational shortly after the successful launch. Nasa won't even had made a decision on Ares or a general direction before then.

Offline Lars_J

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #2 on: 10/27/2009 01:48 am »
Why exactly is this thread needed??? Any SpaceX updates are going to be about Falcon or Dragon anyway. :)

Offline mmeijeri

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #3 on: 10/27/2009 01:53 am »
This thread is for general discussion other than updates. People have complained about side discussions dominating the updates thread.

Example:

First launch of Falcon 9 ends in a big fireball --> updates thread
See, this is why we need EELV/Proton/SDLV/whatever --> this thread
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Offline Chandonn

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #4 on: 10/27/2009 01:54 am »
Why exactly is this thread needed??? Any SpaceX updates are going to be about Falcon or Dragon anyway. :)

Because the actual SpaceX update threads continuously go off topic, and become more "discussion" than "updates".  Some of us don't have the time to wade through comparisions of spacecraft and automobiles, for example (citing a current thread) just to find some news on a current launch.  That's why Updates Threads should be limited to updates and Discussion Threads should be the place for more general discussions.

(hops off soapbox...)

Offline Lars_J

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #5 on: 10/27/2009 02:18 am »
That's fine... But I guess I just don't see this thread being able to stay on topic any more than the old one.
« Last Edit: 10/27/2009 02:18 am by Lars_J »

Offline mmeijeri

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #6 on: 10/27/2009 02:20 am »
That sounds like a good prediction. :) It might help the other thread stay on topic though.
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Offline edkyle99

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #7 on: 10/27/2009 03:55 am »
Why exactly is this thread needed??? Any SpaceX updates are going to be about Falcon or Dragon anyway. :)

Because the actual SpaceX update threads continuously go off topic, and become more "discussion" than "updates".  Some of us don't have the time to wade through comparisions of spacecraft and automobiles, for example (citing a current thread) just to find some news on a current launch.  That's why Updates Threads should be limited to updates and Discussion Threads should be the place for more general discussions.

(hops off soapbox...)

The problem is that "SpaceX updates" come from SpaceX.  Anyone can find those at www.spacex.com .   So why have a "SpaceX Update" thread?

 - Ed Kyle

Offline sdsds

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #8 on: 10/27/2009 06:16 am »
Prediction: The first launch of Spacex's Falcon 9 launcher will be a complete success with first stage burn, stage separation and full 2nd stage burn. Elon Musk will announce that the Falcon 9 launcher is operational shortly after the successful launch. Nasa won't even had made a decision on Ares or a general direction before then.

Prediction:  At least one of the nine first stage Merlins will significantly under-perform, possibly even shut down.  Extended burns by the others will get the vehicle into some kind of orbit.  Elon will call the flight a complete success.  SpaceX detractors will say it shows serious lack of quality control and claim it calls into doubt the entire NewSpace philosophy.

In other words:  more of what SpaceX has been all about!
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Offline Ben the Space Brit

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #9 on: 10/27/2009 10:58 am »
Predictions:

* During the F-9/COTS demonstration program, at least one Dragon will be lost due to a multiple engine-out during the core burn. 

* The upper stage will suffer a string of individually trivial but collectively serious problems that will not be straightened out until the third or fourth 'all up' flight. 

* The Draco hypergolic thruster system will also suffer from some teething troubles. 

* Despite these issues, the Dragon itself will perform above the expectations of many and NASA authorises the first ISS test docking as per the published schedule.

* There will be a significant subset of launches where one or two core engines under-performs, but this will never be serious enough to lead to a LOM.  However, this will give impetus to SpaceX developing a 'Merlin-2', possibly based on RS-84 technology, to allow a reduction in the number of core engines and improvement in reliability.
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Offline ugordan

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #10 on: 10/27/2009 11:24 am »
Predictions:

* During the F-9/COTS demonstration program, at least one Dragon will be lost due to a multiple engine-out during the core burn. 

And for extra 10 points, list the specific engine numbers (1-9) which will be lost.

Seriously, what is the point of these "I predict..." rants at least two months in advance of any actual flight? Bragging rights afterward or something, because it's not something that sparks a discussion - which this thread is supposed to be all about.

Some of the previous, amusingly detailed predictions have already failed to materialize and it's clear they have no real backing in reality and are subsequently forgotten immediately. Unless the one making them happens to get it right which then leads to "I predicted this back in X in this post...".
« Last Edit: 10/27/2009 11:28 am by ugordan »

Offline William Barton

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #11 on: 10/27/2009 11:27 am »
What's the factual basis for these engine-out and under-performing Merlin predictions? Falcon I #1 had a sort of "engine out," but that was a different (ablative) Merlin launching under different conditions, and the aluminum B-nut is no more. Have any of the 3 Merlin C launches actually underperformed? I concede the rest of it. Vacuum Merlin is newish, and Draco hasn't flown in any form, so who knows what will happen, especially given SpaceX's track record of not quite coping with problems they'd previously stated were likely. Personally, I'd be more likely to expect a roll-control problem with the first stage, given it's all TVC, rather than the steerable exhaust thingy. Then again, I haven't really got clue here. Is TVC on all 9 engines? Iirc, wasn't Saturn 1 four outboard gimballed engines and four center fixed?

Offline Chandonn

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #12 on: 10/27/2009 11:43 am »
Why exactly is this thread needed??? Any SpaceX updates are going to be about Falcon or Dragon anyway. :)

Because the actual SpaceX update threads continuously go off topic, and become more "discussion" than "updates".  Some of us don't have the time to wade through comparisions of spacecraft and automobiles, for example (citing a current thread) just to find some news on a current launch.  That's why Updates Threads should be limited to updates and Discussion Threads should be the place for more general discussions.

(hops off soapbox...)

The problem is that "SpaceX updates" come from SpaceX.  Anyone can find those at www.spacex.com .   So why have a "SpaceX Update" thread?

 - Ed Kyle

One-stop shopping.  Also, we sometimes get updates that are NOT on the "official" update sites.

Offline Diagoras

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #13 on: 10/27/2009 12:15 pm »
Not sure whether this should go here or in the SpaceX update thread, or another one altogether.

Anyway, could a SpaceX Falcon 1 launch one of the Google Lunar X Prize robots? Ad Astra (I think that's the name) seems to be the only one building a launch vehicle, so I expect they're counting on someone to help 'em out.
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Offline thomson

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #14 on: 10/27/2009 12:32 pm »
Ad Astra (I think that's the name) seems to be the only one building a launch vehicle, so I expect they're counting on someone to help 'em out.
Arca Space are also developing launcher http://forum.nasaspaceflight.com/index.php?topic=18951.0. An unusual one, I'd say.

Offline Ben the Space Brit

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #15 on: 10/27/2009 01:01 pm »
What's the factual basis for these engine-out and under-performing Merlin predictions?

Factual? None at all.  It is merely a coming together of basic statistics and gut feeling.  Nine engines having to work together seems to be asking for trouble.  Either one will not work entirely correctly or some unforseen interaction between the nine will have affects on them or the vehicle as a whole
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Offline William Barton

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #16 on: 10/27/2009 01:11 pm »
What's the factual basis for these engine-out and under-performing Merlin predictions?

Factual? None at all.  It is merely a coming together of basic statistics and gut feeling.  Nine engines having to work together seems to be asking for trouble.  Either one will not work entirely correctly or some unforseen interaction between the nine will have affects on them or the vehicle as a whole

I just wanted to make sure I hadn't missed something. My gut feeling is, the Cluster's Last Stand theory is wrong and that it's based on some unproven statistical assumptions. Saturn I was at the dawn of the space age, and seemed to work okay despite eight engines having to work together. Can't exactly say the same for N-1, of course, but it's not a fully comparable case, either. To the best of my knowledge, those NK's had never flown successfully before, and still haven't. Theoretically, you'd have to apply that set of statistics to Taurus II when estimating it's chances of success. But only theoretically.

Offline SpacexULA

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #17 on: 10/27/2009 02:02 pm »
One-stop shopping.  Also, we sometimes get updates that are NOT on the "official" update sites.

The new "updates" thread would now have the official updates PLUS:

-Articles in magazines that add new information
-Twitter accounts from people in the know
-Q&A at Conferances
-Changes to the SpaceX website
-Pictures posted by SpaceX employees, and guests

Basically any INFORMATION goes to the other thread, any OPINIONS go in this thread.
No Bucks no Buck Rogers, but at least Flexible path gets you Twiki.

Offline William Barton

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #18 on: 10/27/2009 02:10 pm »
What's the factual basis for these engine-out and under-performing Merlin predictions?

Factual? None at all.  It is merely a coming together of basic statistics and gut feeling.  Nine engines having to work together seems to be asking for trouble.  Either one will not work entirely correctly or some unforseen interaction between the nine will have affects on them or the vehicle as a whole

I just wanted to make sure I hadn't missed something. My gut feeling is, the Cluster's Last Stand theory is wrong and that it's based on some unproven statistical assumptions. Saturn I was at the dawn of the space age, and seemed to work okay despite eight engines having to work together. Can't exactly say the same for N-1, of course, but it's not a fully comparable case, either. To the best of my knowledge, those NK's had never flown successfully before, and still haven't. Theoretically, you'd have to apply that set of statistics to Taurus II when estimating it's chances of success. But only theoretically.

Here's a related question: At the time of Saturn I development, had any US team successfully developed a rocket with more than 2 engines in its first stage? All I can think of is Atlas and Titan I (two engines each [if my understanding the two outboard "engines" on Atlas were one engine with two chambers is correct]). Viking, Vanguard, Redstone, Thor, Jupiter are the big single-engine rockets I can think of. Anything else?

Offline ugordan

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Re: SpaceX: General Falcon and Dragon discussion
« Reply #19 on: 10/27/2009 02:21 pm »
It is merely a coming together of basic statistics and gut feeling.

Out of curiosity, what would those basic statistics and gut feelings have to say for vehicles with a total of 11 and 14 engines?

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